Re: [PATCH] Fix the x86 specializations of atomic_[set|clear]_mask

From: Peter Zijlstra
Date: Thu Oct 16 2014 - 04:02:26 EST


On Wed, Oct 15, 2014 at 04:38:01PM -0400, Patrick Palka wrote:
> This patch fixes a number of issues with these specializations:
>
> 1. The memory operand inside the asm specification is erroneously
> declared read-only instead of read-write.
>
> 2. There is no reason to require the 1st operand of andl/orl to be
> inside a register; the 1st operand could also be an immediate operand.
> So change its specification from "r" to "ir".
>
> 3. Since addr is supposed to be an atomic_t *, the memory operand
> should be addr->counter and not *addr.
>
> 4. These specializations should be inline functions instead of macros.
>
> 5. Finally, the "memory" clobbers are unnecessary, so they should be
> removed. (This is in line with the other atomic functions such as
> atomic_add and atomic_sub, the likes of which do not have a "memory"
> clobber.)

No real problem with this, but I'm going to kill off these functions
when I get a little time :)
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